An ___________ rule is used to define a page block for printed styles.

The correct answer is: B. @page

An @page rule is used to define a page block for printed styles. It is used to specify the page size, margins, and other page properties.

The @important rule is used to override the default style of an element.

The @css rule is used to define a CSS style sheet.

The @html rule is used to define a HTML document.

Here is an example of an @page rule:

@page {
size: A4;
margin: 2cm;
}

This rule will define a page with a size of A4 paper and a margin of 2cm on all sides.